Crimp contacts having two crimp sections arranged on opposite sides of a crimp base are known in the art. An end of a conductor is positioned between the crimp sections and over the crimp base, and the crimp sections are crimped around the end of the conductor, for example, with crimping pliers or a crimping device. The conductor is thus connected both mechanically and electrically to the crimp contact.
Applications of crimp contacts in the mobile field, such as in automobile construction, require weight savings which are made possible by using, for example, aluminum conductor wires. Aluminum, however, forms insulative aluminum oxide from contact with ambient air, and consequently, electrically contacting an aluminum wire is difficult. It is therefore necessary to pierce through the aluminum oxide layer when electrically contacting an aluminum wire for the first time and advantageous to protect the aluminum wire from environmental influences in the case of further use.
Known crimp contacts generally consist of copper, and since aluminum and copper have different standard potentials, it is necessary to impede the ingress of any electrically conductive liquids; even liquids with the slightest impurities. By impeding ingress, it can be ensured that the aluminum does not electrochemically decompose due to the difference in electrical potential. In addition, through such a protection of the aluminum wires, hermetic sealing from ambient air may likewise be possible, which impedes a (renewed) oxidation of the aluminum.
In the prior art, such protection for the aluminum is addressed through self-protecting crimp connections. These known crimp connections are formed by crimp contacts having an insulation crimp, a conductor crimp, and wings or front protection lugs, wherein, in the crimping process, the wings or front protection lugs are crimped such that they block the access to the crimp sleeve. In addition, a self-protecting crimp has sealing agent repositories through which, during crimping, a sealing agent is made available which fills gaps still remaining in the crimped front protection crimp, in the crimped conductor crimp (i.e. between the conductor crimp and the aluminum conductor) and in the insulation crimp (i.e. between the insulation of the aluminum conductor and the insulation crimp) and thus prevents ingress of electrically conductive and/or corrosive liquids along with ambient air.
In the crimping process, the wings are curved in the direction of the receptacle of the conductor so that the wings which are opposite one another touch over an axis of symmetry of the crimp contact which extends in a longitudinal direction and come closer to the crimp base. Since the aluminum oxide layer is formed at all outer surfaces of the aluminum conductor prior to crimping, piercing through this aluminum oxide layer is accomplished during crimping through mechanical contact with the crimp contact; through serrations or indentations formed on the crimp contact
Single strands of the aluminum conductor situated on the inside of the conductor are, however, sometimes not sufficiently mechanically stressed during crimping in order to pierce through the aluminum oxide layer. These single strands situated on the inside are no longer available for the conduction of electrical current due to the aluminum oxide layer formed around them, and the resistance of the aluminum conductor used is increased.
A plug connector 2 according to the prior art comprising a crimp contact 1, a contact member 5 extending in a longitudinal direction 7, and a bearing strip 11 is shown in FIGS. 1-4.
The crimp contact 1 comprises two wings 13 and two crimp sections 15, the crimp sections 15 comprising an insulation crimp 17, a conductor crimp 19 and a front protection crimp 21. The insulation crimp 17, conductor crimp 19, and front protection crimp 21 each extend from one crimp section 15 via a crimp base 23 to a crimp section 15 situated opposite, so that a continuous sleeve, the crimp sleeve 3, is formed. The crimp sleeve 3 encloses a receptacle 24 in which a conductor 43 (not shown) can be received. The crimp sleeve 3 is linked to a bearing strip 11 via a linking bar 9. The linking bar 9, the bearing strip 11, and the contact member 5 are shown purely by way of example. Serrations 25, or indentations, are formed in the conductor crimp 19, and a sealing agent repository 27 is formed in the front protection crimp 21.
The crimp contact 1 is shown in a pre-crimped state 35 in FIG. 2. The front protection crimp 21 is integrally formed with the conductor crimp 19, wherein, in the depiction shown in FIG. 2, the wing 13 separates both crimp regions 19, 21 from one another. On an underside 29 of the crimp contact 1, a step 31 can be seen which distinguishes a transition region 33 between the conductor crimp 19 and the insulation crimp 17. The receptacle 24 for the conductor 43 extends over the conductor crimp 19 and the insulation crimp 17. The conductor insulation (not shown) of a conductor 43 (not shown) can be received in the insulation crimp 17.
The crimp contact is shown in a crimped state 37 in FIGS. 3 and 4. In FIG. 4, in the crimped state 37, the crimp base 23, the crimp sections 15 and the wings 13 are shown, sectioned through the front protection crimp 21 of the crimp contact 1. Since no conductor 43 is disposed in the area of the front protection crimp 21, the crimp sections 15 and the wings 13 are rolled together such that they seal the crimp interior 41. Gaps 51 may remain when the front protection crimp 21 and the wings 13 are crimped.
As shown in FIG. 3, sectioned through the conductor crimp 19 in the crimped state 37, the crimp sections 15 extend from the crimp base 23 substantially perpendicular in a z-direction, and are curved towards one another, abutting in a striking region 39. The crimp base 23 and the crimp sections 15 enclose a crimp interior 41 in which is situated the conductor 43. In the embodiment shown in FIG. 3, the conductor 43 comprises twenty-three single strands 45. The crimp interior 41 is formed by the receptacle 24 during crimping.
If such a crimp contact 1 is used to electrically contact an aluminum conductor 43, then on the aluminum's surfaces exposed to the outer air there is situated an electrically isolating layer of aluminum oxide, with the layer of aluminum oxide having to be pierced through in order to electrically contact the single strand 45 located under the layer of aluminum oxide. A disadvantage of a crimp connection 4 of the prior art becomes clear from FIG. 3. Inner strands 45a are only in mechanical and electrical contact with other single strands 45, but not with the crimp sections 15 or the crimp base 23. The inner strands 45a are not subjected to any sufficiently great mechanical contacting, meaning that the layer of aluminum oxide on the inner strands 45a cannot be pierced through. Electrical conduction via the inner strands 45a is thus impaired and conductivity of the aluminum conductor 43 is lowered.